[NTG-context] \presentationstep: recent changes?

A couple of months ago, Hans posted the attached example in response to a desperate request for a working \presentationstep. I remember having tried it, and it worked at that time. With my current context (2003.1.10), this is no longer the case. The whole text area is covered by the presentationshield, and clicking the Whatever-Button has no effect. I guess there have been changes to the \presentationstep mechanism. Since I would (maybe) like to use this for a publication soon, I'm wondering how to get it working with a recent context. Eckhart